Indian Software Defined Rx. (ISDR)

The ISDR is developed for Students and Radio Amateurs. ISDR is a  low cost 40 meter band receiver.

PC Sound card's MIC jack(stereo) is extensively used for the ISDR. So, the ISDR performance depends on the PC Sound card. The center frequency is 7056 KHz and typical frequency range the receiver covers is about +/- 48 KHz and depends on the PC sound card sampling rate which happens to be 96 KHz. The receivers performance depends on the usage of a good antenna.  

A 28.224MHz  crystal which is used to create stable oscillations.  IC 74HC00 is used as a Local Oscillator of frequency 28.224MHz. The output of the local Oscillator is first divided by  to provide True and Complement signals (0 degrees and 180 degrees) by IC 74HC74. These two signals are agian divided by 2 to provide 0 degree and 90 degree by one more  IC 74HC74. These signals are given as L.O. input to the mixers to drive the P and Q amplifiers through transistor buffers. The output signals P and Q (mono-jacks) are low frequency signals which have a phase difference of 90 degrees. These signals are connected to the MIC jack (stereo) of the PC.

Front Panel  :  Outputs P & Q (mono jacks)
                      ON / OFF switch
                      LED indicator.
Back Panel  :  Antenna connector(UHF/ BNC)
                      12V D.C. binding posts.

Software to be used: Rocky, WinRad, PowerSDR etc. (all software used are free ) 


Block diagram of the ISDR:
Link for Block Diagram PDF: Click Here

The first schematic shows the Regulator circuit and the Local Oscillator circuit.

 Link for Schematic PDF: Click Here

The schematic here shows the complete circuit of the ISDR.


Link for Schematic PDF: Click Here


ISDR PCB:  



List of all the download files available for ISDR:

ISDR - PE
ISDR - Introduction
ISDR - PCB 1, PCB 2 & PCB 3
ISDR - Presentation
ISDR - Assembly

For downloading and installing Rocky and Winrad download the following PDF's for complete instructions and troubleshooting:

Rocky - Click Here
Winrad - Click Here






9 comments:

  1. Hi,can any one tell what is 40 meter band represent... and what is the power of this SDR reciever.

    ReplyDelete
  2. 40 meter band in shortwave region is reserved for Hams or Radio ametuers. It is 7.000 MHz to 7.100 MHz. By convention, 7 to 7.050 are frequencies used for CW or Morse reception and transmission. and 7.050 to 7.100 are the frequencies use for SSB transmission. ( Single Side Band transmissions ). Normally, people use Lower Side Band on 40 meters and use Upper Side Band on 20 meters.( 14.000 to 14.350 MHz )
    -ex VU2caa

    ReplyDelete
  3. I am very happy to get the SDR kit at hand. I have now started assemblying the same and hope to complete ina week or so.I will put up my test results for the benefit of all.

    ReplyDelete
  4. what is the price of the kit and how can we place the order?

    ReplyDelete
    Replies
    1. Hi,

      Please send us an email at the following email id's and we shall get back to you.

      rnd.mipl@gmail.com
      hamr@micronovaimpex.com

      Thank you

      Delete
  5. what is the price of the kit and how can we place the order?

    ReplyDelete
    Replies
    1. Hi,

      Please send us an email at the following email id's and we shall get back to you.

      rnd.mipl@gmail.com
      hamr@micronovaimpex.com

      Thank you
      Delete

      Delete
  6. This comment has been removed by the author.

    ReplyDelete